// values are in mm
cave
BOX
//air
vacuum
 20000  -20000  -20000
 20000   20000  -20000
-20000   20000  -20000
-20000  -20000  -20000
 20000  -20000   20000
 20000   20000   20000
-20000   20000   20000
-20000  -20000   20000
